St. Luke's Blogs

One of the most common recommendations to prevent breast cancer from the American Cancer Society is for women to undergo annual mammograms after their 40th birthday. While mammograms have shown that they can catch breast cancer, there are other things patients need to consider before having a mammogram.

October is breast cancer awareness month and since Idaho ranks last in the nation for mammography screening, it seemed like an appropriate time to discuss breast cancer screening. Dr. Banu Symington, an oncologist with St. Luke's Mountain States Tumor Institute (MSTI), answers common questions about screening mammograms.

Q: What’s the low-down about screening mammograms?

A: When you say breast cancer screening, everyone thinks mammogram. Mammograms are low dose X-ray studies of the breast that can detect architectural distortions and calcium deposits (also known as microcalcifications) in the breasts. Sometimes, these changes can be indicative of breast cancer. Just as we convinced every woman to get a mammogram annually after age 40 or 50 depending on different guidelines, along came a U.S. Preventive Services Task Force (USPTF) study saying annual mammograms should not be performed! What’s going on here? Well the truth is that with the widespread utilization of screening mammograms, we have seen a dramatic increase in the detection of early cancers and even precancerous conditions, but we have not seen any decline in late stage cancers. The hallmark of a successful cancer screening test is a reduction in the number of people presenting with late stage disease. So mammography fails this test.

Q: What are the pitfalls of mammography?

A: Not all cancers cause visible architectural distortion or calcium deposits. Furthermore, many women develop microcalcifications as they age. Most of these calcium deposits are benign (ie not cancerous), and even in the subset where calcium deposits are not benign, most are associated with a precancerous condition known as ductal carcinoma in situ (aka DCIS). The problem is that while we recognize that some women with DCIS go on to develop invasive cancers, we suspect most will not and we cannot tell the patients who will progress to invasive cancer from those who will not. To make matters worse, we now believe that DCIS may be a condition of aging and not always a disease. So many women get surgery, radiation, and even hormonal treatments and are labeled “cancer survivors” for a condition that may never become full blown (ie invasive) breast cancer or may even be a manifestation of aging!! In other words, we have created a large pool of healthy women who believe they have cancer, with all the psychological distress that that such a diagnosis can cause.

Q: What are the costs of overtreatment?

A: In our enthusiasm to win the war on cancer, doctors were initially ignorant of the potential for damage from overtreatment. However, this is an increasingly recognized consequence of cancer treatment. Surgery causes scars, radiation can predispose to further cancers, chemotherapy has many consequences, and anti-estrogen therapy can predispose to blood clots and bone density loss. Thus, the overtreatment of DCIS has many costs-- the financial cost incurred by potentially unnecessary treatment, the physical side effects of treatment, and the emotional consequences of being labeled a cancer “survivor”.

Q: Can mammography detect all cancers?

A: There are three major problem areas for screening mammography. First, some cancers cause a breast lump without any detectable mammographic changes. These are often lobular cancers. In these cases, only biopsy due to concern about an asymmetry or new lump leads to diagnosis. So we cannot catch all types of cancer with mammography. Yet when women are getting annual mammograms, they are often lulled into a false sense of security and do not examine their breasts.

The second problem is aggressive “interval” cancer s. These are rapidly growing cancers that pop up months after a truly negative mammogram. Here again, if a woman is relying on last years “negative screening mammogram” and ignoring a growing lump, she is actually harmed by the false security of a recent negative mammogram.

The third problem area for mammography is breast density. The sensitivity of screening mammography is reduced in women with dense breasts. Previously thought to be an indication of youthful breasts or ongoing exposure to estrogen therapy, it has recently been recognized that mammographically dense breasts may be a familial condition, unrelated to age, that may increase your risk of breast cancer. Ironically, it also increases the chances that your breast cancer will be missed by screening mammography.

Q: What’s the bottom line?

A: Mammograms are imperfect cancer screening tools plagued by false positives and false negatives. In other words, not every mammographic abnormality is cancer and mammography may not always detect the biologically important cancers. Furthermore, reliance on mammograms as a stand alone cancer screening test is foolhardy. A false sense of security after a negative screening mammogram can delay the diagnosis of certain breast cancers. Remember to get a breast exam before the mammogram so any areas that FEEL abnormal can be flagged for further studies. This will increase the likelihood of detecting all cancers.

Q: What is the final word about the RATIONAL use of screening mammograms?

A: Screening cancer studies are intended to be used in people with more than a 10 year life expectancy. So if you are over 75-80 years of age or are younger and very unhealthy, you can skip the SCREENING mammogram. But remember to have a breast exam. If you have pain that is concerning or a new, worrisome lump, you may still need a diagnostic mammogram.

Q: What about MRI mammography?

A: There has been a lot of press lately about MRI mammograms. These studies are extremely sensitive but they are not very specific. So odds are high that a woman getting an MRI mammogram will have an abnormality, but that the abnormality will NOT be cancer. So screening an average risk patient with MRI mammography causes a lot of anxiety and results in many women getting additional tests, including biopsies.

Q: Who should get an MRI mammogram?

A: Women with a high probability of having or getting breast cancer, such as women with the BRCA1/2 mutations. Also, women who will be getting chemotherapy BEFORE they get surgery (ie neoadjuvant chemotherapy recipients) need an MRI mammogram to better define the extent of tumor within the breast without surgery.

Q: What can you do?

A: First and foremost, as you approach 30, talk to your primary care doc about your personal breast cancer risk factors. Having close relatives with breast cancer before 50, any male relatives with breast cancer, or a first degree relative with ovarian cancer should heighten your concern that you may have a familial breast cancer syndrome. If you have a high risk of breast cancer, annual or every other year mammography with regular clinical breast exams may still be the right decision for you. Don’t ignore a new breast lump. Never accept a provider’s statement that you are “too young to have breast cancer”. And remember to get a breast exam before mammography.

Find out more in the following videos about self-breast exams and mammography: